Classical ways to treat liquids using plasmas are by i) generating a plasma in a gas medium which is in contact with the liquid, ii) generating a plasma in bubbled liquid or iii) electrical discharges directly into the liquid. This latter is the richest process in chemical (production of radicals) and physical phenomena (production of shock waves and cavitation), however is also not sufficiently efficient for many applications.
Accordingly, there is a need for improved devices and methods for generating a plasma directly in a liquid.